Light-tracking optical device and application to light concentration

Abstract

An automatic optical coupling device that uses liquid to couple focused light into a light-guide is described. The liquid moves within a chamber or layer via the thermocapillary effect in order to automatically track and couple a moving spot of focused light. Also provided is the application of these coupling devices in an array feeding into a common light-guide, optical designs to improve the performance of these arrays, and the application of such arrays to light collection.

What is claimed is: 
     
       1. A light-guiding structure, comprising:
 a first solid layer, wherein the first solid layer is transparent; 
 a second solid layer; and 
 a fluid light-tracking layer interposed between the first and second solid layers, wherein the fluid light-tracking layer contains a first fluid and a second fluid, wherein the first fluid and the second fluid are immiscible, wherein at least a portion of the first fluid comprises a coupling region located at a local temperature maximum within the fluid light-tracking layer, wherein a light beam incident on the light-guiding structure and striking the coupling region is deflected by an element of the light-guiding structure at an angle sufficient to confine at least a portion of the deflected light beam within the light-guiding structure as the deflected light beam propagates through the light-guiding structure, wherein the local temperature maximum is the result of localized absorption of a portion of the light beam incident on the light-guiding structure, wherein the coupling region self-aligns with the light beam incident on the light-guiding structure, and wherein a cross-sectional area of the coupling region is less than 10% of a fluid light-tracking layer cross-section. 
 
     
     
       2. The light-guiding structure of  claim 1 , wherein the first fluid has a first refractive index, the second fluid has a second refractive index which is less than the first refractive index, and the first solid layer has a third refractive index which is greater than the second refractive index. 
     
     
       3. The light-guiding structure of  claim 1 , wherein a surface of at least one of the first solid layer or the second solid layer is coated with a layer to control fluid wetting. 
     
     
       4. The light-guiding structure of  claim 1 , wherein the first fluid is contained within a plurality of chambers. 
     
     
       5. The light-guiding structure of  claim 1 , wherein the second fluid is contained within a plurality of chambers. 
     
     
       6. The light-guiding structure of  claim 1 , wherein the first fluid and the second fluid are each selected from the group of materials consisting of aqueous solutions, water-soluble fluids, hydrocarbon oils, silicone oils, and fluorocarbon oils. 
     
     
       7. The light-guiding structure of  claim 1 , wherein the light-guiding structure is planar. 
     
     
       8. The light-guiding structure of  claim 1 , wherein the light-guiding structure is curved. 
     
     
       9. The light-guiding structure of  claim 1 , wherein the light beam incident on the light-guiding structure is comprised of a focused light beam. 
     
     
       10. The light-guiding structure of  claim 1 , wherein the first solid layer is a light-guiding layer, wherein the second solid layer is a light-reorienting layer, wherein the light-reorienting layer deflects the light beam incident on the light-guiding structure into the light-guiding layer at an angle sufficient to confine at least a portion of the deflected light beam within the light-guiding layer as the deflected light beam propagates through the light-guiding layer, wherein the first fluid is a coupling fluid and comprises a coupling fluid layer adjacent to the light-reorienting layer, wherein the second fluid is a cladding fluid and comprises a cladding fluid layer adjacent to the light-guiding layer and adjacent to the coupling fluid layer, and wherein the cladding fluid layer further comprises an aperture formed at the coupling region when the light beam is incident on the light-guiding structure, wherein the aperture is filled with the coupling fluid when the light beam is incident on the light-guiding structure, and wherein the aperture is eliminated from the cladding fluid layer when the light beam is not incident on the light-guiding structure. 
     
     
       11. The light-guiding structure of  claim 10 , wherein the light-reorienting layer is comprised of a light-scattering material. 
     
     
       12. The light-guiding structure of  claim 11 , wherein the light-reorienting layer is reflective and comprised of a sawtooth mirror. 
     
     
       13. The light-guiding structure of  claim 11 , wherein the light-reorienting layer is transmissive and comprised of a prism array. 
     
     
       14. The light-guiding structure of  claim 11 , wherein the light-reorienting layer is transmissive and comprised of a light-scattering material. 
     
     
       15. The light-guiding structure of  claim 11 , wherein the first fluid has a first refractive index, the second fluid has a second refractive index which is less than the first refractive index, and the first solid layer has a third refractive index which is greater than the second refractive index. 
     
     
       16. The light-guiding structure of  claim 11 , wherein a surface of at least one of the first solid layer or the second solid layer is coated with a layer to control fluid wetting. 
     
     
       17. The light-guiding structure of  claim 11 , wherein the first fluid is contained within a plurality of chambers. 
     
     
       18. The light-guiding structure of  claim 11 , wherein the second fluid is contained within a plurality of chambers. 
     
     
       19. The light-guiding structure of  claim 11 , wherein the first fluid and the second fluid are each selected from the group of materials consisting of aqueous solutions, water-soluble fluids, hydrocarbon oils, silicone oils, and fluorocarbon oils. 
     
     
       20. The light-guiding structure of  claim 11 , wherein the light-guiding structure is planar. 
     
     
       21. The light-guiding structure of  claim 11 , wherein the light-guiding structure is curved. 
     
     
       22. The light-guiding structure of  claim 11 , wherein the light beam incident on the light-guiding structure is comprised of a focused light beam. 
     
     
       23. The light-guiding structure of  claim 1 , wherein the second solid layer is a light-reorienting layer, wherein the first fluid is a coupling fluid and comprises a coupling fluid layer adjacent to the first solid layer, wherein the second fluid is a cladding fluid and comprises a cladding fluid layer adjacent to the light-reorienting layer and adjacent to the coupling fluid layer, wherein the light-reorienting layer deflects the light beam incident on the light-guiding structure into the coupling fluid layer at an angle sufficient to confine at least a portion of the deflected light beam within the light-guiding structure as the deflected light beam propagates through the light-guiding structure, and wherein the cladding fluid layer further comprises an aperture formed at the coupling region when the light beam is incident on the light-guiding structure, wherein the aperture is filled with the coupling fluid when the light beam is incident on the light-guiding structure, and wherein the aperture is eliminated from the cladding fluid layer when the light beam is not incident on the light-guiding structure. 
     
     
       24. The light-guiding structure of  claim 23 , wherein the coupling fluid layer in combination with the first solid layer guide the light beam through a bulk portion of the first solid layer and through a bulk portion of the coupling fluid layer. 
     
     
       25. The light-guiding structure of  claim 23 , wherein the coupling fluid layer guides the light beam through a bulk portion of the coupling fluid layer. 
     
     
       26. The light-guiding structure of  claim 23 , wherein the light-reorienting layer is comprised of a light-scattering material. 
     
     
       27. The light-guiding structure of  claim 23 , wherein the light-reorienting layer is reflective and comprised of a sawtooth mirror. 
     
     
       28. The light-guiding structure of  claim 23 , wherein the light-reorienting layer is transmissive and comprised of a prism array. 
     
     
       29. The light-guiding structure of  claim 23 , wherein the light-reorienting layer is transmissive and comprised of a light-scattering material. 
     
     
       30. The light-guiding structure of  claim 23 , wherein the first fluid has a first refractive index, the second fluid has a second refractive index which is less than the first refractive index, and the first solid layer has a third refractive index which is greater than the second refractive index. 
     
     
       31. The light-guiding structure of  claim 23 , wherein a surface of at least one of the first solid layer or the second solid layer is coated with a layer to control fluid wetting. 
     
     
       32. The light-guiding structure of  claim 23 , wherein the first fluid is contained within a plurality of chambers. 
     
     
       33. The light-guiding structure of  claim 23 , wherein the second fluid is contained within a plurality of chambers. 
     
     
       34. The light-guiding structure of  claim 23 , wherein the first fluid and the second fluid are each selected from the group of materials consisting of aqueous solutions, water-soluble fluids, hydrocarbon oils, silicone oils, and fluorocarbon oils. 
     
     
       35. The light-guiding structure of  claim 23 , wherein the light-guiding structure is planar. 
     
     
       36. The light-guiding structure of  claim 23 , wherein the light-guiding structure is curved. 
     
     
       37. The light-guiding structure of  claim 23 , wherein the light beam incident on the light-guiding structure is comprised of a focused light beam. 
     
     
       38. The light-guiding structure of  claim 1 , wherein the first solid layer is a light-guiding layer, wherein the second solid layer is a light-reorienting layer, wherein the light-reorienting layer deflects the light beam incident on the light-guiding structure into the light-guiding layer at an angle sufficient to confine at least a portion of the deflected light beam within the light-guiding layer as the deflected light beam propagates through the light-guiding layer, wherein the second fluid is a cladding fluid and comprises a cladding fluid layer adjacent to the light-guiding layer and adjacent to the light-reorienting layer, wherein the first fluid is a coupling fluid, wherein the coupling region comprises a droplet of the coupling fluid, wherein the droplet of the coupling fluid is within the cladding fluid layer and free to move within the cladding fluid layer, and wherein the droplet of the coupling fluid is in contact with both the light-guiding layer and the light-reorienting layer. 
     
     
       39. The light-guiding structure of  claim 38 , wherein the light-reorienting layer is comprised of a light-scattering material. 
     
     
       40. The light-guiding structure of  claim 38 , wherein the light-reorienting layer is reflective and comprised of a sawtooth mirror. 
     
     
       41. The light-guiding structure of  claim 38 , wherein the light-reorienting layer is transmissive and comprised of a prism array. 
     
     
       42. The light-guiding structure of  claim 38 , wherein the light-reorienting layer is transmissive and comprised of a light-scattering material. 
     
     
       43. The light-guiding structure of  claim 38 , wherein the first fluid has a first refractive index, the second fluid has a second refractive index which is less than the first refractive index, and the first solid layer has a third refractive index which is greater than the second refractive index. 
     
     
       44. The light-guiding structure of  claim 38 , wherein a surface of at least one of the first solid layer or the second solid layer is coated with a layer to control fluid wetting. 
     
     
       45. The light-guiding structure of  claim 38 , wherein the first fluid is contained within a plurality of chambers. 
     
     
       46. The light-guiding structure of  claim 38 , wherein the second fluid is contained within a plurality of chambers. 
     
     
       47. The light-guiding structure of  claim 38 , wherein the first fluid and the second fluid are each selected from the group of materials consisting of aqueous solutions, water-soluble fluids, hydrocarbon oils, silicone oils, and fluorocarbon oils. 
     
     
       48. The light-guiding structure of  claim 38 , wherein the light-guiding structure is planar. 
     
     
       49. The light-guiding structure of  claim 38 , wherein the light-guiding structure is curved. 
     
     
       50. The light-guiding structure of  claim 38 , wherein the light beam incident on the light-guiding structure is comprised of a focused light beam. 
     
     
       51. The light-guiding structure of  claim 1 , wherein the second fluid comprises a layer adjacent to the first solid layer and adjacent to the second solid layer, wherein the coupling region comprises a droplet of the first fluid, wherein the droplet of the first fluid is within the second fluid and free to move within the second fluid, and wherein the droplet of the first fluid contains reorienting elements that deflect the light beam incident on the light-guiding structure into the layer of the second fluid at an angle sufficient to confine at least a portion of the deflected light beam within the light-guiding structure as the deflected light beam propagates through the light-guiding structure. 
     
     
       52. The light-guiding structure of  claim 51 , wherein the first solid layer is a light-guiding layer, wherein the second fluid is a cladding fluid and comprises a cladding fluid layer adjacent to the light-guiding layer and adjacent to the second solid layer, wherein the first fluid is a coupling fluid, and wherein the droplet of the coupling fluid deflects the light beam at an angle sufficient to confine at least a portion of the deflected light beam within the light-guiding layer. 
     
     
       53. The light-guiding structure of  claim 51 , wherein the second fluid layer in combination with the first solid layer guide the light beam through a bulk portion of the first solid layer and through a bulk portion of the second fluid layer. 
     
     
       54. The light-guiding structure of  claim 51 , wherein the second fluid layer guides the light beam through a bulk portion of the second fluid layer. 
     
     
       55. The light-guiding structure of  claim 51 , wherein the second solid layer is a light-absorbing layer. 
     
     
       56. The light-guiding structure of  claim 51 , further comprising a light-absorbing layer, wherein the light absorbing layer is adjacent to the second solid layer. 
     
     
       57. The light-guiding structure of  claim 51 , wherein the first fluid has a first refractive index, the second fluid has a second refractive index which is less than the first refractive index, and the first solid layer has a third refractive index which is greater than the second refractive index. 
     
     
       58. The light-guiding structure of  claim 51 , wherein a surface of at least one of the first solid layer or the second solid layer is coated with a layer to control fluid wetting. 
     
     
       59. The light-guiding structure of  claim 51 , wherein the first fluid is contained within a plurality of chambers. 
     
     
       60. The light-guiding structure of  claim 51 , wherein the second fluid is contained within a plurality of chambers. 
     
     
       61. The light-guiding structure of  claim 51 , wherein the first fluid and the second fluid are each selected from the group of materials consisting of aqueous solutions, water-soluble fluids, hydrocarbon oils, silicone oils, and fluorocarbon oils. 
     
     
       62. The light-guiding structure of  claim 51 , wherein the light-guiding structure is planar. 
     
     
       63. The light-guiding structure of  claim 51 , wherein the light-guiding structure is curved. 
     
     
       64. The light-guiding structure of  claim 51 , wherein the light beam incident on the light-guiding structure is comprised of a focused light beam.